Thursday, March 08, 2012

Sightings for Thrusday March 8

Sainte-Anne-de-Bellevue, Morgan Arboretum: Over the past couple of days, many birds have been sighted; Barred Owl (Chouette rayée) seen right along the snowshoe trail (photo), The Red-Bellied woodpecker(s) (Pic à ventre roux) have also made another appearance, Red-Winged Blackbirds (Carouge à épaulettes) can now be heard again, Canada Geese (Bernache du Canada) as well. Lots of Pileated woodpeckers (Grand pic) as well as Purple finches (Roselins pourprés), and all of the "regulars" - Chris Cloutier
About the Hermann's Gull
There has been considerable discussion about the gull that I found on Saturday in Ottawa. The matte grey plumage, contrasting white head, dark wing tips lacking mirrors, and all dark bill were interesting enough for me to put out an alert on the bird as a Heerman's. Fortunately several dozen people got out to see the bird, and some distant photos obtained; here is the best of them:

The viewing conditions were poor, but most people were satisfied with the identification as a Heerman's Gull. Nonetheless, there were several features which bothered me about it. Most importantly, I was bothered by the fact that as far as I could see the bill was entirely black, not red based, except for a pale tip (nail). This might have been an artifact of lighting, red being the first colour to fade in low light, but the bills of nearby birds showed well. Secondly, while the bird was clearly darker than the Ring-billed Gulls it was associating with, it did not seem to be dark enough to be a typical Heerman's Gull. Thirdly, the configuration of the white on the head seemed wrong, and the demarkation between the white head and the grey underparts and nape, too sharply defined (almost like a dark hooded gull in reverse). So what is it? On balance I think the features just mentioned, make it unlikely to have been a Heerman's. I briefly flirted with the idea that it could be a Grey Gull, but here too there are problems; while Grey Gull has a black bill, the proportions are wrong as it has a conspicuously long, slender bill. So where does this leave us? A hybrid is one possibility, although it is hard to imagine what the pairing might have been (Heerman's x California?) Another possibility is a partially melanistic bird. Melanistic gulls are rare but occur. The photographs I have found show birds that are uniformly sooty, much darker than the Deschennes bird. Another possibility is a "grey washed" bird. Fortunately there are photographs of this aberrant plumage, for example this grey Ring-billed Gull photographed in the USA:

Even more interesting is this white headed, grey Black-legged Kittiwake in Quebec:

Other than the yellow bill and the proportions, the latter bird is virtually identical to the Ottawa gull. I now believe that the Ottawa gull was such a grey washed individual, probably, based on structure and probabilities, a Ring-billed Gull. This is not a plumage I was familiar with and appears to be very rare (cf it is not mentioned for Ring-billed Gull in Malling & Olson's "Gulls of Europe, Asia and North America"). The one feature that does not appear to fit this hypothesis is the dark bill, as, at least in the photographs I have found, the normal bill colour is retained.

I would like to thank the many people who came out to see or look for the bird, and those who commented on my facebook posting and replied to my various e-mails. In particular I would like to thank Jean Dubois and Gary McNulty (Quebec) for sharing their thoughts, Bruce MacTavish (Newfoundland) and Alvaro Jaramello (California) for their insights, and Olivier Barden for his instructive picture of the Kittiwake. - Mark Gawn Ottawa
Vaudreuil-Dorion: Two Turkey vultures soaring over the junction Highway 20 and 540 this morning. It feels like spring because I see also 18 Common grackles,  15 American robins, 16 Blue jays and 3 Wild turkeys. These turkeys are present for several days on Blvd. Cité des jeunes in the field in front of Wolseley Plumbing.

Deux urubus à tête rouge en vol plané ont passé au dessus de la jonction autoroute 20 et 540 à Vaudreuil-Dorion ce matin. Ça sent le printemps car j'ai aussi vu 18 quiscales bronzés, 15 merles d'amérique et 16 geais bleus et 3 dindons sauvages. Ces dindons sont présents depuis quelques jours sur le boul. Cité des jeunes dans le champ en face du commerce Plomberie Wolseley. - Michel Juteau

Cap-d'Espoir, Pointe du Cap: Eearlier this afternoon, my first Black Guillemots (2), Common Murre (1), 9 Black scoters

Pointe du Cap: en début d'après-midi , mes premiers Guillemots à miroir (2), Guillemot marmette (1), 9 Macreuses à bec jaune - Albini Couture

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